A composite for preventing ice adhesion, facilitating the removal of ice, snow, and frozen contaminants is desirable. The application fields are very broad, encompassing critical areas such as aircraft, vehicles, marine, wind turbine, and electric power cables.
Many low surface energy materials, such as silicon-containing polymers [1], fluoropolymers [2] and their composites are claimed as anti-icing coatings, such as: U.S. Pat. No. 8,202,620, U.S. Pat. No. 8,193,294, U.S. Pat. No. 7,897,667, U.S. Pat. No. 7,915,371, U.S. Pat. No. 7,910,683, U.S. Pat. No. 7,261,768, U.S. Pat. No. 7,261,768, U.S. Pat. No. 7,202,321, U.S. Pat. No. 6,809,169, U.S. Pat. No. 6,797,795, U.S. Pat. No. 6,733,892, U.S. Pat. No. 6,579,620, U.S. Pat. No. 6,432,486, U.S. Pat. No. 6,395,345, U.S. Pat. No. 6,363,135, U.S. Pat. No. 6,183,872, U.S. Pat. No. 6,153,304, U.S. Pat. No. 6,114,448, U.S. Pat. No. 6,084,020, U.S. Pat. No. 6,068,911, U.S. Pat. No. 5,904,959, U.S. Pat. No. 5,747,561, U.S. Pat. No. 5,736,249, U.S. Pat. No. 5,336,715, U.S. Pat. No. 5,188,750, U.S. Pat. No. 5,187,015, U.S. Pat. No. 5,075,378, U.S. Pat. No. 5,045,599, U.S. Pat. No. 5,008,135, U.S. Pat. No. 4,565,714, and U.S. Pat. No. 4,301,208.
The NASA Lewis Research Center, which operates the world's largest refrigerated Icing Research Tunnel (IRT), has performed icing research for over 50 years. The studies conducted by NASA and other researchers have concluded that fluoropolymers, siloxane resins, their composites, as surface coatings are inadequate for anti-icing applications [3].
Superhydrophobic nano-micron hierarchical structures of lotus leaves have been studied since 1977 [5]. Various approaches for mimicking the surface topography and surface chemistry of lotus leaves have been attempted, resulting in the launch of biomimetic products [6, 7]. The main methods developed so far have been: 1) layer-by-layer assembly, 2) polymer film roughening, 3) chemical vapor deposition, 4) sol-gel process, 5) phase separation, 6) hydrothermal synthesis, and 7) coating with composites of nanoparticles. The following are typical examples of US patents that are related to superhydrophobic coatings: U.S. Pat. No. 8,241,508, U.S. Pat. No. 8,236,379, U.S. Pat. No. 8,216,674, U.S. Pat. No. 8,211,969, U.S. Pat. No. 8,202,614, U.S. Pat. No. 8,187,707, U.S. Pat. No. 8,153,233, U.S. Pat. No. 8,147,607, U.S. Pat. No. 8,137,751, U.S. Pat. No. 8,067,059, U.S. Pat. No. 8,043,654, U.S. Pat. No. 8,017,234, U.S. Pat. No. 7,998,554, U.S. Pat. No. 7,985,475, U.S. Pat. No. 7,985,451, U.S. Pat. No. 7,968,187, U.S. Pat. No. 7,943,234, U.S. Pat. No. 7,914,897, U.S. Pat. No. 7,754,279, U.S. Pat. No. 7,722,951, U.S. Pat. No. 7,704,608, U.S. Pat. No. 7,695,767, U.S. Pat. No. 7,485,343, U.S. Pat. No. 7,419,615, U.S. Pat. No. 7,291,628, U.S. Pat. No. 7,258,731, U.S. Pat. No. 7,253,130, U.S. Pat. No. 7,211,605, U.S. Pat. No. 7,150,904, U.S. Pat. No. 6,743,467, U.S. Pat. No. 6,649,222, U.S. Pat. No. 3,391,428
However, superhydrophobic surfaces do not always shown low ice adhesion properties. Secondly, anti-icing properties deteriorate by repeated icing/de-icing cycles due to the destruction of very thin and fragile nano/micron hierarchical structures. Thirdly, prolonged exposure to high humidity levels leads to high ice bonding forces due to ice forming in and getting trapped into inter-asperity spaces [4].